Roddy grew up in Fennybrook, Scotland. The only entertainment available to him as a child was a coal bucket pulled around by a fat, bald goat who could not go fast enough for the children to throw up. Roddy has seen many strange things, including a man getting hit in the belly with a cannonball.
At some point, Roddy seems to have gained great computer programming skills. He was an employee of Apex, and was the first to discover the flaw in the Pinnacle Chip that led to the creation of the Freakazoid. Guitierrez attempted to kill Roddy, but failed. Roddy briefly gave Dexter his first insight into his abilities, before being kidnapped by Guitierrez and escaping into the Internet. Once Guitierrez gained access to the flaw, he booted Roddy from the Internet, and Roddy subsequently became Freakazoid's ally. Roddy is prone to anger and pushing Freakazoid too hard, particularly when he decides Freakazoid should learn telekinesis, leading to Freakazoid mentally withdrawing after accidentally hitting himself in the head with a brick thirty-seven times. Dexter's oblivious parents still know Roddy only as Dexter's driving instructor, not questioning this ruse even after Roddy rescues them from Chesky Beresch Prison in the Eastern European state of Vukanova.
Upon first returning from the Internet in "The Wrath of Guitierrez," Roddy has lightning bolts in his hair, similar to Freakazoid (and Guitierrez in his Freakazoid form). However, the lightning bolts disappeared in Roddy's subsequent appearances.
Roddy's euphemism of choice is "Crud!"
- Mission: Freakazoid
- Two Against Freak
- Normadeus (his only line, "Crud!" is recycled audio from another episode)
- The producers attempted to get Mike Meyers to play Roddy MacStew.
- Roddy is bald underneath his hat in "Freakazoid and Friends," but has a full head of hair in "Mission: Freakazoid."
- "If I can disconnect it, the system will be as helpless as a man with big apples for feet!" (Mission: Freakazoid)
- "Networks are fickle! They'll drop you like a man with big oak fingers!" (Two Against Freak)
- "By the soiled trousers of Argus!" (Two Against Freak)
- "Can you hear, or is there a goblin in your head eating my words?!" (Two Against Freak)